Electromechanical assembly controlled by sensed voltage

ABSTRACT

An electromechanical assembly is provided controlled by voltage across a motor or with an electronic system. The electromechanical assembly includes a control circuit coupled to sense voltage at the motor or within the electronic system, and an electromechanical actuator energized by the voltage sensed by the control circuit. A movable element is movable by the electromechanical actuator from an operational position to a quiesced position when the voltage sensed by the control circuit falls below a quiesced threshold. In certain embodiments, the voltage being sensed is across a motor of an air-moving assembly, which resides within a support structure, or the voltage being sensed is within the electronic system, which resides within the support structure, and the movable element is an interlock element which interlocks to the support structure to prevent removal of one or more components from the structure when sensed voltage is above the quiesced threshold.

BACKGROUND

In many server applications, processors along with their associatedelectronics (e.g., memory, disk drives, power supplies, etc.) arepackaged in removable drawer or subsystem configurations stacked withinan electronics rack or frame comprising information technology (IT)equipment. In other cases, the electronics may be in fixed locationswithin the rack or frame. As circuit densities continue to increase atall levels of packaging, there is an ever-growing need for providingcontinuous cooling to the electronics rack, including the electronicsubsystems thereof. As one solution, a cooling apparatus may be providedwhich includes one or more air-moving assemblies (e.g., axial fans orcentrifugal fans) which facilitate moving an airflow through theelectronics rack, usually front-to-back.

In certain implementations, multiple air-moving assemblies may beprovided in association with one or more drawers or electronic systems(or subsystems) in order that the assemblies may be concurrentlymaintainable, such that if one fails, the failure does not stop airflowthrough the electronic system, and thus negatively affect operationalavailability of computing resources to the customer. In the event that anon-quiesced air-moving assembly is mistakenly removed, the fan orimpeller wheel may still be rotating at a high speed, for instance, at4000 RPMs or above, and have significant momentum, due to the mass ofthe fan or impeller. This action could potentially result in injury tothe operator removing the air-moving assembly.

SUMMARY

In one aspect, the shortcomings of the prior art are overcome andadditional advantages are provided herein through the provision of anapparatus which includes an electromechanical assembly coupled to asystem comprising at least one of a motor or an electronic system tomonitor voltage at the motor or electronic system. The electromechanicalassembly includes: a control circuit coupled to sense voltage at themotor or within the electronic system; an electromechanical actuatorenergized by the voltage sensed by the control circuit at the motor orwithin the electronic system; and a movable element associated with andmovable by the electromechanical actuator, the electromechanicalactuator moving the movable element from an operational position to aquiesced position when the voltage sensed by the control circuit at themotor or within the electronic system falls below a quiesced threshold.

In another aspect, an apparatus is provided which includes an air-movingassembly residing within a support structure in operative position, andan electromechanical assembly coupled to monitor the air-movingassembly. The electromechanical assembly includes: a control circuitcoupled to sense voltage at one or more motor windings of the air-movingassembly; an electromechanical actuator energized by the voltage sensedby the control circuit at the one or more motor windings of theair-moving assembly; and a movable element associated with and movableby the electromechanical actuator, the electromechanical actuator movingthe movable element from an operational position to a quiesced positionwhen the voltage sensed by the control circuit at the one or more motorwindings of the air-moving assembly falls below a quiesced threshold.

Additional features and advantages are realized through the techniquesof the present invention. Other embodiments and aspects of the inventionare described in detail herein and are considered a part of the claimedinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

One or more aspects are particularly pointed out and distinctly claimedas examples in the claims at the conclusion of the specification. Theforegoing and objects, features, and advantages of one or more aspectsof the invention are apparent from the following detailed descriptiontaken in conjunction with the accompanying drawings in which:

FIG. 1 is an elevational depiction of one embodiment of an electronicsrack, which may include one or more apparatuses, in accordance with oneor more aspects of the present invention;

FIG. 2 is a plan view of one embodiment of an electronics drawer layoutillustrating multiple air-moving assemblies at an air inlet side of thelayout, and which may include one or more apparatuses, in accordancewith one or more aspects of the present invention;

FIG. 3A depicts another embodiment of an electronics drawer or chassiswith multiple air-moving assemblies disposed at an air outlet side ofthe chassis, and which may include one or more apparatuses, inaccordance with one or more aspects of the present invention;

FIG. 3B depicts one embodiment of an air-moving assembly of FIG. 3A,shown removed from the chassis, and which may be part of or monitored byan apparatus, in accordance with one or more aspects of the presentinvention;

FIG. 4 depicts one partial embodiment of an apparatus comprising anair-moving assembly, such as depicted in FIG. 3B, and an associatedelectromechanical assembly, in accordance with one or more aspects ofthe present invention;

FIG. 5 depicts the electromechanical assembly of FIG. 4, in accordancewith one or more aspects of the present invention;

FIG. 6 is an electrical schematic of one embodiment of a control circuitof the electromechanical assembly of FIGS. 4 & 5, shown coupled to sensevoltage at one or more motor windings of the air-moving assembly, inaccordance with one or more aspects of the present invention;

FIG. 7A is an elevational view of the apparatus of FIG. 4, shown withthe air-moving assembly in operative position within a chassis, and aninterlock element of the associated electromechanical assembly inquiesced position indicative of the air-moving assembly being inquiesced state, in accordance with one or more aspects of the presentinvention;

FIG. 7B depicts the apparatus of FIG. 7A, with the interlock elementshown in operational position, interlocking with the chassis to preventremoval of the air-moving assembly from the chassis, in accordance withone or more aspects of the present invention;

FIG. 8 depicts an alternate embodiment of a movable element of anelectromechanical assembly interlocked to a support structure, inaccordance with one or more aspects of the present invention;

FIG. 9A depicts another embodiment of a moveable element of anelectromechanical assembly with the movable element interlocked to asupport structure, in accordance with one or more aspects of the presentinvention;

FIG. 9B depicts the apparatus of FIG. 9A, with the movable element ofthe electromechanical assembly shown in quiesced position, retractedfrom the support structure opening, in accordance with one or moreaspects of the present invention;

FIG. 10A depicts one embodiment of a partially assembled electronicsrack, with an electronics drawer shown in operative position within theelectronics rack, the electronics drawer including an electromechanicalassembly, in accordance with one or more aspects of the presentinvention;

FIG. 10B is a partial cutaway, upper plan view of the electronics rackand drawer of FIG. 10A, depicting the electromechanical assembly to besimilar to that shown in FIGS. 4-7B, in accordance with one or moreaspects of the present invention;

FIG. 10C is a partial enlargement of the electronics rack and drawer ofFIG. 10B, with the interlock element of the electromechanical assemblyshown in quiesced position, in accordance with one or more aspects ofthe present invention;

FIG. 10D depicts the enlarged view of FIG. 10C, with the interlockelement shown in operational position, in accordance with one or moreaspects of the present invention;

FIG. 10E depicts the assembly of FIG. 10D, with the interlock element inoperational position shown contacting a portion of the electronics rackand preventing removal of the electronics drawer from the electronicsrack, in accordance with one or more aspects of the present invention;

FIG. 11A depicts another partial embodiment of an electronics drawerwith a cover and an electromechanical assembly similar, for instance, tothat depicted in FIGS. 4-7B, locking the cover in position over one ormore components of the electronics drawer when the movable element ofthe assembly is in operational position, in accordance with one or moreaspects of the present invention;

FIG. 11B depicts the electronics drawer of FIG. 11A, with the movableelement of the electromechanical assembly shown in quiesced position,allowing for opening of the cover and thus access to the one or morecomponents of the electronics drawer beneath the cover, in accordancewith one or more aspects of the present invention;

FIG. 12A is a further embodiment of an electromechanical assembly,wherein the electromechanical assembly mechanically couples to one ormore louvers disposed at, for instance, the air inlet side or air outletside of an air-moving assembly, to direct actuation of the louvers basedon sensed voltage at one or more motor windings of the air-movingassembly, in accordance with one or more aspects of the presentinvention;

FIG. 12B depicts the apparatus of FIG. 12A, with the movable element ofthe assembly shown in operational position, forcing open the one or morelouvers to facilitate airflow through the air-moving assembly, inaccordance with one or more aspects of the present invention;

FIG. 13A illustrates a further embodiment of an electromechanicalassembly, wherein the movable element of the electromechanical assemblyis shown in operational position, not loading one or more springscoupling the assembly to one or more louvers, with the louvers shown ina quiesced, closed orientation, in accordance with one or more aspectsof the present invention; and

FIG. 13B depicts the assembly of FIG. 13A, with the movable element inquiesced position, shown loading the springs to apply a bias to the oneor more louvers to reduce the airflow force required to subsequentlyopen the louvers, in accordance with one or more aspects of the presentinvention.

DETAILED DESCRIPTION

Reference is made below to the drawings, where the same referencenumbers used throughout different figures designate the same or similarcomponents.

FIG. 1 depicts (by way of example) one embodiment of an electronics rack100 with a plurality of electronic subsystems or drawers 101 to becooled. In the embodiment illustrated, electronic systems, subsystems101 are air-cooled by cool airflow 102 ingressing via an air inlet 110,and exhausting out an air outlet 111 as hot airflow 103. One or moreair-moving assemblies 108 may be provided at the air inlet sides ofelectronic subsystems 101 and/or one or more air-moving assemblies 109may be provided at the air outlet sides of electronic subsystems 101 tofacilitate airflow through the individual subsystems 101 as part of thecooling apparatus of electronics rack 100. By way of example, air-movingassemblies 108 at the air inlets to electronic subsystems 101 may be orinclude axial fan assemblies, and air-moving assemblies 109 disposed atthe air outlets of electronic subsystems 101 may be or includecentrifugal fan assemblies. One or more of electronic subsystems 101 mayinclude heat-generating components to be cooled of a computer system,electronics system, or information technology (IT) equipment. Forinstance, one or more of the electronic subsystems 101 may include oneor more processors and associated memory.

Electronics rack 100 may also include, by way of example only, one ormore bulk power assemblies 104 of an AC to DC power supply assembly. ACto DC power supply assembly further includes, in one embodiment, a framecontroller, which may be resident in the bulk power assembly 104 and/orin one or more electronic subsystems 101. Also illustrated in FIG. 1 isone or more input/output (I/O) drawer(s) 105, which may also include aswitch network. I/O drawer(s) 105 may include, as one example, PCI slotsand disk drivers for the electronics rack.

In implementation, a three-phase AC source may feed power via an ACpower supply line cord 106 to bulk power assembly 104, which transformsthe supplied AC power to an appropriate DC power level for output viadistribution cable 107 to the plurality of electronic subsystems 101 andI/O drawer(s) 105. The number of electronic subsystems installed in theelectronics rack is variable, and depends on customer requirements for aparticular system. Further, although described with reference tomultiple electronic subsystems 101, the air-moving assemblies discussedherein could reside within, for instance, bulk power assembly 104, orI/O drawer(s) 105. Again, the particular electronics rack configurationof FIG. 1 is presented by way of example only, and not by way oflimitation.

FIG. 2 depicts one embodiment of an electronic subsystem 101 layoutwhich includes a chassis 200 being air-cooled utilizing one air-coolingapproach, where one or more air-moving assemblies 205 provide forcedairflow 215 in operational state to cool multiple electronic components210 within electronic subsystem 101. Cool air is taken in through an airinlet 201 and heated air is exhausted out an air outlet 202 of theelectronic subsystem. The multiple components 210 to be cooled mayinclude, by way of example, multiple processor modules 212, as well asmultiple arrays of memory modules 213 (e.g., dual-in-line memory modules(DIMMs)) and multiple rows of memory support modules 214 (e.g., DIMMcontrol modules). In one implementation, air-cooled heat sinks (notshown) may be coupled to one or more of processor modules 212, memorymodules 213, and/or memory support modules 214 to facilitate dissipationof heat therefrom.

In the depicted example of FIG. 2, the air-moving assemblies 205, aswell as the electronic components, reside within chassis 200 containingor supporting the electronic subsystem. Also, as depicted, theair-moving assemblies 205 disposed at the air inlet side 201 of theelectronic subsystem may be redundant fan assemblies, which concurrentlyprovide the cooling airflow 215 across or through the electroniccomponents of the electronic subsystem.

FIG. 3A partially depicts an alternate embodiment of an electronicsubsystem 101 layout which includes a chassis 300, and redundantair-moving assemblies 310 disposed at an air outlet side 302 of theelectronic subsystem, with the air inlet side 301 being, by way ofexample, at an opposite side of chassis 300. Redundant air-movingassemblies 310 are operatively positioned within chassis 300 within, forinstance, respective receiving tracks 305, which are a part of oraffixed to chassis 300. In FIG. 3A, air-moving assemblies 310 are shownoperational, with an airflow 315 exiting the air outlets thereof.

FIG. 3B depicts one embodiment of air-moving assembly 310 of FIG. 3A. Inthis embodiment, air-moving assembly 310 is depicted as a centrifugalfan assembly with a relatively large air inlet opening 311 in a lowersurface thereof, exposing the centrifugal blower 313, and an air outlet312, which may have a grating 307 as a safety feature. As noted above,in many systems today, air-moving assemblies may be designed to beconcurrently maintainable, so that one assembly entering into a quiescedstate does not significantly impact system cooling, and thus operationalavailability of computing resources to a customer. In the event that anoperating air-moving assembly 310 is removed, the fan or impeller wheelmay be spinning at a high speed, and have significant momentum due toits mass. This could result in injury to the operator removing theassembly, particularly in a centrifugal fan design such as illustratedin FIG. 3B, where there is a relatively large air inlet 311 within theassembly.

One possible solution to the issue is to provide a fixed grill withopenings smaller than an operator's fingers at the air assembly's inlet.However, this could significantly impede airflow through the assembly.An alternate approach is to disallow redundancy for concurrentreplaceability, which is undesirable, since a customer could experiencea computing outage due to a single air-moving assembly transitioning toquiesced state, for instance, due to a failure.

As a solution, disclosed herein are apparatuses and methods whichaddress, in part, the above-noted drawbacks to existing, currentlymaintainable, air-moving assemblies. The apparatuses may include, forinstance, an electromechanical assembly coupled to monitor a motor, suchas the motor of an air-moving assembly. The electromechanical assemblyincludes a control circuit coupled to sense voltage at one or more motorwindings of the motor, and an electromechanical actuator energized bythe voltage sensed by the control circuit at the one or more motorwindings. In addition, the assembly includes a movable element movableby the electromechanical actuator. The movable element may be part ofthe electromechanical actuator, such as an extendible shaft or othermovable member of the electromechanical actuator, and/or include aspring mechanism or one or more other structures controllable by theelectromechanical actuator. The electromechanical actuator moves themoveable element from an operational position to a quiesced positionwhen the voltage sensed by the control circuit at the one or more motorwindings of the motor falls below a predefined, quiesced thresholdlevel. As will be understood by the examples provided herein, theelectromechanical actuator and movable element may be configured suchthat the movable element is either extended or retracted in operationalposition, with the quiesced position being the other of the extended orretracted position for a particular application.

As noted, in one or more implementations, the motor is part of anair-moving assembly, and subsequent to switching off or interruptingpower to the air-moving assembly, voltage at the one or more motorwindings remains for a period of time due to back electromotive forcebeing generated by the air-moving assembly as the rotor slows. Theair-moving assembly may reside within a support structure in operativeposition, such as a chassis or electronics drawer, and the movableelement may be or include an interlock element or tab which interlocksto the support structure to prevent removal of one or more componentsfrom the support structure when the sensed voltage at the one or moremotor windings is above the quiesced threshold. By way of example, thesupport structure may include the chassis within which the air-movingassembly resides in operative position, and the one or more componentsmay include the air-moving assembly itself. In such an embodiment, theinterlock element prevents removal of the air-moving assembly from thechassis when the sensed voltage at the one or more motor windings isabove the quiesced threshold. In one or more other implementations, thesupport structure includes an electronics drawer and an electronicsrack, and the interlock element is associated with the electronicsdrawer and interlocks with the electronics rack to prevent removal ofthe electronics drawer from the electronics rack when the sensed voltageat the one or more motor windings is above the quiesced threshold.

In certain embodiments, the control circuit of the electromechanicalassembly includes a bridge rectifier electrically coupled to the one ormore motor windings, and a comparator coupled to compare the sensedvoltage to the quiesced threshold, where the quiesced threshold ispredetermined as a safe threshold voltage which allows for removal ofthe one or more components. For instance, the electromechanical actuatorlocks the one or more components, such as a the air-moving assembly, inplace until power to the one or more motor windings of the motor isterminated (for instance, the motor is switched off), and the sensedvoltage at the motor windings is below the quiesced threshold, where thequiesced threshold is predefined to correlate to a safe motor RPMs toallow access to the one or more components.

In one or more implementations, the movable element is or includes aninterlock element or tab which interlocks with a cover over at leastpart of an electronics drawer. The interlock element prevents opening ofthe cover when the sensed voltage is above the quiesced threshold. Byway of example, the movable element may be or include a movable memberof the electromechanical actuator, and the electromechanical actuatormay further include a solenoid, which surrounds, at least in part, themovable member. In one or more embodiments, the movable element mayinclude, at least in part, a spring mechanism coupled to theelectromechanical actuator.

In certain further embodiments, the motor may be part of an air-movingassembly, and the movable element may couple to at least one louverdisposed at an air inlet or an air outlet of the air-moving assembly.The movable element may be configured to facilitate pivoting of the atleast one louver between an operational position and a quiesced positiondepending, in part, on the sensed voltage at the one or more motorwindings. For instance, the movable element may be coupled to directactuation of the louvers based on sensed voltage at the one or moremotor windings of the air-moving assembly. Alternatively, the movableelement may be coupled to apply a spring biasing to the one or morelouvers to reduce an airflow force otherwise required to open thelouvers when the mechanical element is in quiesced position (indicativeof the air-moving assembly being in quiesced state), and to not load thelouvers when the movable element is in operational position.

The above-described electromechanical assemblies may, in one or morefurther implementations, alternatively be coupled to monitor voltagewithin an electronic system, such as at one or more capacitors of anelectronic system, to ensure energy levels within the system are safebefore the electromechanical assembly allows service personnel access tothe system. In such implementations, rather than monitoring voltage at amotor or a motor winding, the electromechanical assembly, and inparticular the control circuit, monitors voltage at one or morelocations within the electronic system, and the electromechanicalactuator moves the movable element from the operational position to thequiesced position when the sensed voltage within the electronic systemfalls below the quiesced threshold. Thus, in one or more embodiments,the movable element of the electromechanical assembly may be configuredto ensure that system energy is bled down to a safe level beforeallowing access to the electronic system.

As one detailed example, FIG. 4 depicts one partial embodiment of anapparatus, generally denoted 400, in accordance with one or more aspectsof the present invention. Apparatus 400 includes, by way of exampleonly, an air-moving assembly 310, such as the air-moving assemblydescribed above in connection with FIGS. 3A & 3B, wherein in oneexample, air-moving assembly 310 may be a centrifugal fan assembly. Inthe embodiment illustrated, an air-moving assembly 310 is shown withoutits cover and air outlet grating, and with an electromechanical assembly410 being provided in association with air-moving assembly 310. Inparticular, electromechanical assembly 410 is illustrated mounted withinthe housing of air-moving assembly 310, by way of example. As will beunderstood from the description provided herein, this placement ofelectromechanical assembly 410 within the housing of the air-movingassembly 310 is presented as one detailed example only. The conceptsdisclosed herein are not limited to the location of theelectromechanical assembly relative to the motor being monitored.

FIG. 5 depicts in greater detail one embodiment of electromechanicalassembly 410 of FIG. 4. As illustrated, electromechanical assembly 410includes, in one or more implementations, a substrate or a card 500supporting a control circuit 501 and an electromechanical actuator 502which comprises or is associated with a movable element or component 503to move the movable component 503 between an operational position, and aquiesced position. By way of example, in one embodiment,electromechanical actuator 502 is configured such that when sensing anoperational voltage at the one or more motor windings of, for instance,the air-moving assembly, then the movable component 503 is extended, inthe operational position in this example, and when the sensed voltagefalls below the quiesced threshold, then the movable component 503 isretracted, in the quiesced position. In this context, extended andretracted may be defined in relation to, for instance, electromechanicalactuator 502 or card 500. As noted, the extension of movable component503 in operational position represents one embodiment only of theconcepts disclosed herein. Movable component 503 is movable, forinstance, translatable, between the operational position and thequiesced position, and thus has a defined travel 504. Note that althoughdepicted herein as providing linear actuation, the electromechanicalactuator 502 could alternatively, in one or more implementations, beimplemented as a rotary-style actuator depending, for instance, on theconfiguration of the movable element and the use for which theelectromechanical assembly is designed. A signal light 505 may also beprovided, driven, for instance, by control circuit 501. In one or moreembodiments, signal light 505 may be ON when the movable element is inoperational position, and automatically switched OFF upon translation ofthe movable element to the quiesced position. In one or moreimplementations, signal light 505 may be or include one or morelight-emitting diodes.

FIG. 6 is an electrical schematic of one embodiment of certaincomponents of the electromechanical assembly 410 of FIG. 5. In theembodiment shown, the control circuit 501 electrically couples to one ormore motor windings L1, L2, L3, of a motor 600. For instance, theelectromechanical assembly may be electrically coupled to one or moremotor windings of an air-moving assembly, such as described above. Inthe example depicted, a three-phase motor 600 is illustrated, which iselectrically driven by a drive circuit 602 via supply lines 601. By wayof example, control circuit 501 may include a bridge rectifier 610 and acomparator 612. For instance, a three-phase rectifier may be employed tomonitor the three-phase (voltage) waveform from motor 600 and provide afull wave rectification of the signals to a DC level. This resultant DClevel is proportional to the voltage at the motor windings or leads.When drive circuit 602 powers motor 600, the driving voltage willdetermine this DC voltage at the bridge rectifier 610. However, when thedrive circuit is disconnected, the voltage at the motor windings will beproportional to the motor speed due to back electromagnetic force of themotor 600. Comparator 612 is configured to allow current throughelectromechanical actuator if the DC value is above a quiescedthreshold, which is a predetermined value that correlates to a speed ator above which (for example) the motor and the air-moving assemblyshould remain locked in place.

There are many potential implementations for the threshold concept, witha resistor R1 in-series with a solenoid coil 615 (of the actuator) beingone example. In one or more implementations, the electromechanicalactuator will be OFF if the DC voltage at the bridge rectifier 610 isbelow the quiesced threshold, or dropout voltage of the actuator. Athigher values, the actuator resistance and resistance R1 will determineif the electromechanical actuator (for instance, solenoid coil) isenergized or not. A Zener diode D1 may be provided as a clamp to ensurethat solenoid coil 615 voltage does not become too high. Signal light505 may be, for instance, in-series with solenoid coil 615, and if thecoil is ON (meaning the movable element is in operational position (forexample, a locked position)), then the signal light is lit. Thus, whensignal light 505 is OFF, it is safe to remove the one or morecomponents, such as the air-moving assembly, being protected by theelectromechanical assembly.

FIGS. 7A & 7B depict one example of electromechanical assembly 410 ofFIGS. 4-6 in operation. In FIG. 7A, the movable component 503 is inquiesced position, retracted into the housing of air-moving assembly310, with the air-moving assembly 310 shown in operational positionwithin chassis 300. In this view, power to air-moving assembly 310 isassumed to be off, and little or no back electromagnetic force is beinggenerated at the motor windings of the air-moving assembly.

In FIG. 7B, the motor of the air-moving assembly may be operational,with a sensed voltage at one or more of the motor windings energizingthe electromechanical actuator of electromechanical assembly 410 toextend (in this example) movable component 503 to the operationalposition. In the embodiment depicted, sufficient travel is provided toallow movable component 503 to extend through an aligned, interlockopening 700 in chassis 300 configured to facilitate the interlockfunction described herein. In this position, movable component 503 is aninterlock element which locks the air-moving assembly 310 housing inplace within chassis 300, and thereby prevents removal of the air-movingassembly from the chassis while sensed voltage at the one or more motorwindings is at or above the predefined, quiesced threshold level.

Implementation of the electromechanical assembly described above inconnection with FIGS. 4-7B can vary, including for instance, in terms ofplacement of the electromechanical assembly, as well as configuration ofthe assembly.

FIG. 8 depicts one alternate configuration of electromechanical assembly410, wherein a movable element 800 is provided which includes movablecomponent 503 described above, as well as a base 801, a spring mechanism802, and an interlock tab or plunger 803. In the operational positionillustrated, movable element 800, and in particular, interlock tab 803extends through opening 700 in chassis 300 to interlock one or morecomponents associated with the electromechanical assembly 410 to chassis300 to prevent removal of the one or more components, with theair-moving assembly being one example of one component which may beinterlocked to the chassis using the assembly described herein. In thisconfiguration, spring mechanism 802 advantageously facilitates partialdecoupling interlock tab 803 from mechanical actuator 502. Should anoperator attempt removal of the component(s) locked by theelectromechanical assembly, then spring mechanism 802 provides a degreeof movement while still ensuring interlocking of the assembly to thechassis. In the embodiment depicted, an extension feature 804 isprovided in association with, for instance, interlocking tab 803 toallow mechanical override of electromechanical assembly 410 should, forinstance, the assembly fault with movable element 800 in the operationalposition, notwithstanding, for example, that the associated motor beingmonitored is quiesced. In the depicted embodiment, an opening 805 may beprovided in chassis 300 to allows for insertion of an override tool 810to engage extension feature 804 and allow, for instance, manual movementof interlocking tab 803 from opening 700 to allow (for instance) forremoval of the associated one or more components.

FIGS. 9A & 9B depict another implementation of an electromechanicalassembly, in accordance with one or more aspects of the presentinvention. In this configuration, a movable element 900 replaces movableelement 800 of the embodiment of FIG. 8, and includes, for instance,moveable component 503, base 801, spring mechanism 802, and an L-shapedpivot arm 901 pivotably mounted 903 to a structure disposed withinchassis 300 when in operational position, such as to the housing ofair-moving assembly 310. In this particular implementation, theelectromagnetic actuator 502′ is alternately configured from theelectromechanical actuator 502 described above in connection with FIGS.4-8. In particular, in one or more implementations of electromechanicalactuator 502′, the actuator and component 503 are configured such thatmovable component 503 is retracted relative to the actuator when inoperational position, and is extended relative to the actuator when inquiesced position. As noted, one of ordinary skill in the art couldconfigure or select the actuator and/or control circuit such thatmovable component 503 is either extended or retracted when in theoperational position, that is, is either a push-type actuator or apull-type actuator, as desired for a particular implementation.

In FIG. 9A, the operational position is depicted, which in thisconfiguration, means that the movable component 503 is retracted,allowing the end of L-shaped pivot arm 901 to be pulled up, and theinterlocking tab 902 of L-shaped pivot arm 901 to extend through opening700 in chassis 300, thereby interlocking the one or more componentsassociated with the electromechanical assembly relative to the chassis.

In FIG. 9B, the motor being monitored is assumed quiesced, with themovable component 503 shown extended to compress spring mechanism 802against L-shaped pivot arm 901, pivoting interlocking tab 902 upwardsfrom opening 700, to allow for removal of, for instance, air-movingassembly 310 from chassis 300.

FIGS. 10A-10E depict a further implementation of an apparatus comprisingan electromechanical assembly such as disclosed herein.

Referring collectively to FIGS. 10A-10C, the apparatus is shown toinclude, in one embodiment, an electronics rack 1000 (shown partiallyassembled) and one or more electronics drawers 1010. In one or moreimplementations, electronics rack 1000 may be similar to electronicsrack 100 described above in connection with FIG. 1, with electronicsdrawer 1010 being one example of an electronics subsystem within anelectronics rack 1000. Together, electronics rack 1000 and electronicsdrawer 1010 define a support structure for one or more componentswithin, for instance, electronics drawer 1010. In the depictedimplementation, one or more electromechanical assemblies 410 may beassociated with, for instance, disposed within, electronics drawer 1010to, for example, facilitate interlocking electronics drawer 1010 toelectronics frame 1000 when sensed voltage at one or more motorsassociated with electronics drawer 1010 or sensed voltage within theelectronics drawer is above a quiesced threshold. By way of example, theone or more motors may be associated with one or more air-movingassemblies, such as discussed herein. The air-moving assemblies may belocated within electronics drawer 1010 or, alternatively, external toelectronics drawer 1010, for instance, elsewhere within electronics rack1000. One or more wires or conductive lines (not shown) may be providedto electrically couple electromechanical assembly 410 to the motorwindings in order to sense voltage across the motor windings. As noted,sensed voltage within the electronics drawer or within an electronicsystem associated with the electronics drawer could alternatively bemonitored by the electromechanical assembly to ensure that energy levelswithin the system or drawer are at a safe level before theelectromechanical assembly allows removal of the electronics drawer fromthe rack.

As illustrated in FIGS. 10B & 10C, in one or more implementations,electromechanical assembly 410 is disposed at, for instance, a frontcorner of electronics drawer 1010 adjacent to, for instance, a faceplate 1011 of the electronics drawer 1010, housing or chassis. Asillustrated in FIG. 10C, face plate 1011 contacts a stop plate 1001 ofelectronics rack 1000 when electronics drawer 1010 is operativelypositioned within electronics rack 1000. In FIGS. 10B & 10C, movableelement or component 503 is shown in quiesced position which, in theabove-described implementation of electromechanical assembly 410 ofFIGS. 4-7B, is a retracted position. In this quiesced position, theassociated motor windings being monitored are assumed to have zerovoltage or the voltage level which corresponds to a level below thedefined quiesced threshold level. When the motor is operating or backelectromotive force being generated is greater than the quiescedthreshold of electromechanical assembly 410, movable element orcomponent 503 is in an operational position, which as noted, in theelectromechanical assembly 410 depicted is in an extended position, asillustrated in FIG. 10D.

In one or more implementations, movable element or component 503 isconfigured with a sufficient length, and electromechanical assembly 410is positioned within electronics drawer 1010 so as to allow movablecomponent 503 to project through an aligned opening in the housing orchassis of electronics drawer 1010, as illustrated in FIG. 10D. As shownin FIG. 10E, in the particular implementation depicted, movablecomponent 503 is sized and positioned to contact in operational positionwith stop plate 1001 of electronics rack 1000. Thus, one or moreelectromechanical assemblies 410 may be provided within one or moreelectronic subsystems, such as one or more electronics drawers 1010 ofelectronics rack 1000, to interlock the subsystem or drawer within theelectronics rack while motor winding voltage being monitored is at avoltage level above the quiesced threshold defined to be a safethreshold below which the associated electronics subsystem, system,drawer, etc., may be removed.

As noted, the electromechanical assembly disclosed herein could beapplied in a number of ways to restrict access to one or morecomponents. FIGS. 11A & 11B depict a further variation.

In FIG. 11A, an electronic system 1101 is partially illustrated, whichincludes an electronics board or substrate 1105 supporting a pluralityof components of the electronic system. By way of example, thecomponents may include one or more processor modules 1102, one or morememory cards 1103, and one or more PCI cards 1104, as well as othercomponents. In this configuration, a hinged cover 1100 is provided overone or more of the components within electronic system 1101. Forinstance, hinged cover 1100 may be provided over the one or moreprocessor modules 1102 and the one or more memory cards 1103. With sucha configuration, it may be possible to service a portion of thecomponents within electronic system 1101 when the cover is closed, suchas, for instance, PCI cards 1104, while other components of theelectronic system, such as the processor modules and memory cards, arenot serviceable or accessible. Hinged cover 1100 may thus function as asafety cover, and an electromechanical assembly 410 (such as describedherein) may be employed to latch or lock cover 1100 in position asillustrated in FIG. 11A, when a sensed voltage within or associated withthe electronic system 1101 is above a quiesced threshold.

More particularly, with a configuration of electromechanical assembly410 such as described above in connection with FIGS. 4-7B, movableelement or component 503 in operational position is extended, andelectromechanical assembly 410 may be located so that movable component503 extends into an appropriately configured receiving opening (notshown) in cover 1100 to interlock with the cover and prevent opening ofcover 100 while the movable element remains in the operational position.

As illustrated in FIG. 11B, once the sensed voltage falls below aquiesced threshold for safe removal of one or more components beneaththe cover, then the moveable component 503 is transitioned byelectromechanical assembly 410 to the quiesced position, which in oneembodiment, is the retracted position, where the movable element iswithdrawn from interlocking with cover 1100, thus allowing for openingof the cover and access to the one or more components beneath the cover.

Note that the above-described implementation of FIGS. 11A & 11Badvantageously may be employed to prevent access to one or morecomponents where the energy level of the components or system may beabove a level that a person could safely contact, defined, for instance,by UL safety limits. With this approach, the hinged cover is lockedsafely in place until, for instance, the system energy level is bleddown to a safe level, as represented by the monitored system voltagebeing below the quiesced threshold. Note that in one or moreimplementations, energy within the system could be monitored or sensedat one or more points in the system, such as, for example, at one ormore capacitors or other components.

FIGS. 12A-12B depict one alternative use for an electromechanicalassembly such as disclosed herein. In these figures, electromechanicalassembly 410 is assumed to be associated with air-moving assembly 310,with air-moving assembly 310 shown in operative position within chassis300. As shown, electromechanical assembly 410 couples via a couplinglinkage 1200 to one or more louvers 1210 disposed at the air inlet sideor air outlet side of air-moving assembly 310. Coupling linkage 1200movably couples movable component 503 to louvers 1210, such that in thequiesced position illustrated in FIG. 12A, electromechanical assembly410 directly closes louver(s) 1210 to, for instance, preventrecirculation of air through air-moving assembly 310. When, forinstance, the air-moving assembly 310 is operational, or the sensedvoltage at the fan's motor is above the quiesced threshold, then themovable component 503 is in operational position, which opens thelouvers to facilitate airflow through the assembly.

FIGS. 13A & 13B depict a further variation, wherein electromechanicalassembly 410 is coupled to provide weight compensation to one or morelouvers 1310 at the air inlet or air outlet of air-moving assembly 310.In the embodiment depicted in FIGS. 13A & 13B, air-moving assembly 310is shown in operational position within chassis 300. In thisconfiguration, the louver(s) 1310 is shown uncompensated in FIG. 13A,and weight-compensated in FIG. 13B, using a coupling 1300 connected tomovable component 503 of electromechanical assembly 410 which includesspring-biasing 1305. In FIG. 13A, element 305 is shown extended, and thespring-biasing 1305 is in relaxed, un-extended state.

In FIG. 13B, the electromechanical assembly 410 has transitioned movablecomponent 503 to the quiesced position, applying a load tospring-biasing 1305 to, for instance, reduce the airflow force requiredto open the one or more louvers 1310.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprise” (andany form of comprise, such as “comprises” and “comprising”), “have” (andany form of have, such as “has” and “having”), “include” (and any formof include, such as “includes” and “including”), and “contain” (and anyform contain, such as “contains” and “containing”) are open-endedlinking verbs. As a result, a method or device that “comprises”, “has”,“includes” or “contains” one or more steps or elements possesses thoseone or more steps or elements, but is not limited to possessing onlythose one or more steps or elements. Likewise, a step of a method or anelement of a device that “comprises”, “has”, “includes” or “contains”one or more features possesses those one or more features, but is notlimited to possessing only those one or more features. Furthermore, adevice or structure that is configured in a certain way is configured inat least that way, but may also be configured in ways that are notlisted.

The corresponding structures, materials, acts, and equivalents of allmeans or step plus function elements in the claims below, if any, areintended to include any structure, material, or act for performing thefunction in combination with other claimed elements as specificallyclaimed. The description of the present invention has been presented forpurposes of illustration and description, but is not intended to beexhaustive or limited to the invention in the form disclosed. Manymodifications and variations will be apparent to those of ordinary skillin the art without departing from the scope and spirit of the invention.The embodiment was chosen and described in order to best explain theprinciples of one or more aspects of the invention and the practicalapplication, and to enable others of ordinary skill in the art tounderstand one or more aspects of the invention for various embodimentswith various modifications as are suited to the particular usecontemplated.

What is claimed is:
 1. An apparatus comprising: an electronics rack; anelectromechanical assembly disposed within the electronics rack andcoupled to a system, comprising a motor, with the electromechanicalassembly monitoring voltage at the motor, the electromechanical assemblycomprising: a control circuit coupled to sense the voltage at the motor;an electromechanical actuator energized by the voltage sensed by thecontrol circuit at the motor; and a movable interlock element associatedwith and movable by the electromechanical actuator, theelectromechanical actuator moving the movable interlock element from anoperational position physically interlocking one or more components ofthe system to a quiesced position not physically interlocking the one ormore components when the voltage sensed by the control circuit at themotor falls below a quiesced threshold, the one or more componentscomprising an air-moving assembly, and the motor being part of theair-moving assembly.
 2. The apparatus of claim 1, wherein theelectromechanical assembly is coupled to monitor the motor, the motorbeing part of the air-moving assembly, and the sensed voltage beingsensed voltage at one or more motor windings of the motor, and wheresubsequent to switching off the air-moving assembly, the voltage at theone or more motor windings being sensed results from back electromotiveforce being generated by the air-moving assembly.
 3. The apparatus ofclaim 2, wherein the air-moving assembly resides within a supportstructure in operative position, and wherein the movable interlockelement interlocks to the support structure when in the operationalposition, to prevent removal of one or more components from the supportstructure, and moves to the quiesced position when the sensed voltage atthe one or more motor windings falls below the quiesced threshold, toallow removal of the one or more components from the support structure.4. The apparatus of claim 3, wherein the control circuit comprises abridge rectifier electrically coupled to the one or more motor windings,and a comparator for comparing the sensed voltage to the quiescedthreshold, the quiesced threshold being predetermined as a safethreshold to allow for removal of the one or more components.
 5. Theapparatus of claim 1, wherein the movable interlock element comprises,at least in part, a movable member of the electromechanical actuator,and wherein the electromechanical actuator further comprises a solenoidsurrounding, at least in part, the movable interlock member.
 6. Theapparatus of claim 1, wherein the movable interlock element comprises,at least in part, a spring mechanism coupled to the electromechanicalactuator.
 7. An apparatus comprising: an electromechanical assemblycoupled to a system comprising at least one of a motor or an electronicsystem to monitor voltage at the motor or within the electronic system,the electromechanical assembly comprising: a control circuit coupled tosense voltage at the motor or within the electronic system; anelectromechanical actuator energized by the voltage sensed by thecontrol circuit at the motor or within the electronic system; a movableinterlock element associated with and movable by the electromechanicalactuator, the electromechanical actuator moving the movable interlockelement from an operational position to a quiesced position when thevoltage sensed by the control circuit at the motor or within theelectronic system falls below a quiesced threshold, the operationalposition being one of an extended position or a retracted position, andthe quiesced position being the other of the extended position or theretracted position; and wherein the electromechanical assembly iscoupled to monitor voltage at the motor, the motor being part of anair-moving assembly, and the sensed voltage being sensed voltage at oneor more motor windings of the assembly, and the movable interlockelement couples to at least one louver disposed at one of an air inletor an air outlet of the air-moving assembly, the movable interlockelement facilitating pivoting of the at least one louver between anoperational orientation and a quiesced orientation, dependent, in part,on the sensed voltage at the one or more motor windings.
 8. An apparatuscomprising: an electronics rack; an air-moving assembly residing withinthe electronics rack, within a support structure in operative position;and an electromechanical assembly coupled to monitor the air-movingassembly, the electromechanical assembly comprising: a control circuitcoupled to sense voltage at one or more motor windings of the air-movingassembly; an electromechanical actuator energized by the voltage sensedby the control circuit at the one or more motor windings of theair-moving assembly; and a movable interlock element associated with andmovable by the electromechanical actuator, the electromechanicalactuator moving the movable interlock element from an operationalposition, physically interlocking the air-moving assembly within thesupport structure, to a quiesced position, not physically interlockingthe air-moving assembly within the support structure, when the voltagesensed by the control circuit at the one or more motor windings of theair-moving assembly falls below a quiesced threshold, the operationalposition being an extended position, and the quiesced position being theretracted position.
 9. The apparatus of claim 8, wherein the movableinterlock element interlocks to the support structure when in theoperational position, to prevent removal of one or more components fromthe support structure, and moves to the quiesced position when thesensed voltage at the one or more motor windings falls below thequiesced threshold, to allow removal of the one or more components fromthe support structure.
 10. The apparatus of claim 8, wherein the movableinterlock element interlocks with a cover of an electronics drawer withwhich the air-moving assembly is associated, the movable interlockelement preventing opening of the cover when the sensed voltage at theone or more motor windings is above the quiesced threshold.
 11. Theapparatus of claim 8, wherein the movable interlock element couples toat least one louver disposed at one of an air inlet or an air outlet ofthe air-moving assembly, the movable element facilitating pivoting ofthe at least one louver between an operational orientation and aquiesced orientation, dependent, in part, on the sensed voltage at theone or more windings.